题目内容
如图所示,在范围很大的水平向右的匀强电场中,一个电荷量为-q的油滴,从A点以速度v竖直向上射
人电场.已知油滴质量为m,重力加速度为g,当油滴到达运动轨迹的最高点B时,测得它的速度大小恰为v/2,问:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241224203771638.jpg)
(1)电场强度E为多大?
(2)A点与最高点的电势差UAB为多少?
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082412242034665.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241224203771638.jpg)
(1)电场强度E为多大?
(2)A点与最高点的电势差UAB为多少?
(1)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122420377488.gif)
(2)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122420393563.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122420377488.gif)
(2)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122420393563.gif)
(1)设油滴从A到最高点B运动时间为t
----------------------------------(1)
水平方向
----------------------(2)
由(1)(2)得
4分
(2)由动能定理
---------------------------------- (3) 2分
竖直方向
-------------------------------------------------(4) 2分
得
2分
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122420424305.gif)
水平方向
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122420439413.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122420455458.gif)
由(1)(2)得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122420377488.gif)
(2)由动能定理
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241224205021042.gif)
竖直方向
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122420517435.gif)
得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122420393563.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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